--branch, stage 2

Show branch:file that is being operated on.

I had to make ActionItem a type and not a type class because
withKeyOptions' passed two different types of values when using the type
class, and I could not get the type checker to accept that.

Command/DropKey.hs

@@ -42,7 +42,7 @@ seek o = do
 
 start :: Key -> CommandStart
 start key = do
-	showStart' "dropkey" key key
+	showStart' "dropkey" key (mkActionItem key)
 	next $ perform key
 
 perform :: Key -> CommandPerform